Back in 1997, several hundred Japanese schoolchildren suffered seizures watching an episode of Pokemon that had brief intervals of flashing lights. The strobing was only a fraction of the 60 Hz refresh rate used in today's 3-D shutter glasses. Still, Japan's NHK won't broadcast in 3-D until it completes a minimum five-year study on whether it could trigger latent adverse health effects.

Tom Randolph, CEO of Kerner Technologies, worries hardcore 3-D gamers might fall prey to seizures and recommends shutter-glasses makers increase their refresh rates to a minimum 120 Hz. But Randolph says if your eyes aren't feeling distress, chances are your brain isn't either. "I think watching 3-D for two hours is safe, even on a red-blue anaglyph. And people who don't feel good are smart enough to walk out."